Electric brake.



No. 677,026. Patented F. w. GARRETT. ELECTRIC BRAKE.

[Application filed Oct. 24, 1900.

(No Model.)

June 25, I90l.

3 Sheets-Sheet l.

WITNESSES I Patented June 25, l90l. F. W. GARRETT.

ELECTRIC BRAKE.

(Appiicntion filed Oct. 24, 1900.

(Na Model.)

mmnoq BM-mQdMw WI TNESSfS Rb nranuar.

No. 677,026. Patented lune 25, I901. F. W. GARRETT.

ELEGTFHG BRAKE. (Application filed cm. 24, 1900. (No Model.) 3 Sheets-8heet 3.

NM ugwk I III.-

45 lar view showing a modification.-

\ The letter A designates the UNIT D STATES Partner OFFICE.

.lli' Olt T THE l'AITlEtAlN STEEL COMPANY, OF PENNSYLVANIA.

ELECTRBC BRAKE.

$IEG3LFICATION forming part of Letters Patent No. iii 7,92%, dated. June 25, 1801.

Application filed October 24,1900. Serial lie. 34,231. (lilo model.)

Yb will whont (It Hut/J concern.-

Be it known that I, FRANK. W GARRETT, of Jolmstown in the county oi. Gambria and Stateof Pennsylvania, have invented a new and useful Im pro vement in Electric Brakcspf which the following is a full, clear, and exact description, reference beingzhad to the accompanying drawings, which form a part of this specification.

My invention has relation to electric brakes for electric-railway cars, and more pariicularly n that class of brakes in which the car moto" s are connected to run as generators in a local circuit driven by the momentum of the moving car, the energy of which is in this manner consumed, the current generated being also used in Whole or part in the application of friction braking devices. 4

The invention is designed to projvide a simzo ple and efficient braking arrangement of this class; and it consists in the combinationflvith a motor or motors and a suitable don't-rollingswitch forconnccting the same to run as generators in alocal circ it, of an improved. electromagnetic fllGliOii-liiiilifi arranged to be actuated by the current generatedin said local. circuit and to operate directly upon the motor shaft or shafts, The circuit connections of the energizing-coils of this brake are controlled 0 by the said switch, which may be arranged to provide for their energization and the resultant frictional braking effort at the time the motors are first connectcdin the local circuit or not until after the speed of the car 5 has been somewhat reduced.

My invention also consists in the novel construction, arrangemcntyand combination of parts, all as hereinafter described, and-point ed out in ,the appended claims.-

4o In theaccompanying drawings, Figure l is an end elevation of a railway electric'motor, showing my improved electromagnetic brake applied thereto. Fig. 2 isa detail View of the brake on a largerscale. 3 is a siini- Fig. 4 is a diagram showing one arrangement-of circuits which. may be employed in the use of my invention with two'motors, and. Fig. 51s asiinilar view showing a somewhat iiifterentcircuit arrangement.

or casing of an railway electric motor, and i3 its armature-shaft. (J is a brake member which is rigidly secured on the said shaft in the form of a circular disk or wheel having apo- 55 ripheral braking-surface, which preferably consists of a detachable rim c, which can be readily removed and replaced when Worn.

M indicates brake-magnets having polopieoes m, in the form of shoes which are adapted to the peripheral surface of thebrake member 0. i 11 cores of these magnets are carried by a be. D, of magnetic material, and in-the arrangement shown one of these cores I is wound with a large coil M and the other one with a few turns of wire'M 'Thc harD is pivoted at d, and its other end has anex- Ltension d, which engages a loop a, on the moitor-franie or other suitable support and is [engaged by a screw E, by means of which it 'ma'y be adjusted against the action. of a retracting 's'pring S. The coil M is connected in the local circuit of the car-motors when the latter are running as generators and is energized by the current generated in said circult, thereby establishing a magnetic circuit which includesdts pole-piece, the brake memii herb, the pole pieoe and core of the other magnet, and the portion of the bar D which connects the two magnets. This circuit is closed, with the exception of the short air; gaps between the pole-pieces m andithe brak ing member C, and as the barv D is 'movable the said pole-pieces are drawn. into braking contact withthe surface 0. The coil M21115) be made to assist in this action; but its principal function is to neutralize residual magnetism when the coil M is decuergized, and thus permit the spring S to retract the bar I). 9o

In the modification shown in Figrdthe'bar I) is supported by links G and two retractingsprings S.

This brake may be connected in any suitable circuit, and the circuit arrangements 5 v shown in Figs. 4 and. 5 merely illustrate two practical arrangements out of many. In Fig. 4, CS indicates a combined power and brake controlling switch for two motors, whose field coils are designated F and F respectively, IO'O and'their armatures A'A ,'respectively. This controller has the usual drum carrying a pin rality of contacts S, which cooperate with the stationary contact-fingers 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, and 14 in the seven running positions indicated by the vertical lines 1, 2, 3, 4", 5, 6, and 7 to regulate the power and speed of the motors, and in the four po- ,sitions 1, 2", 3", and 4 to connect the motors in a closed localcircuit to run as generators. The drum CS is turned in one direction from ,10 its open circuit or elf position for the positions 1 to 7, inclusive, and in the opposite direction for the positions 1 to 4, inclusive. AS is an-auxiliary switch whose movable member P is automatically shifted from enr5 gagement with the contacts p p to engagement with the contacts 13 11 when the drum is turned to its braking positions, and backv again when the drum is turned to its power positions.- Asthis switch .io'rms no part of my present invention andis 'I'nerely incident in series with each other between the blow out coil BOGof the controller and the auxil- 5 iary switch AS. Thecoils M are connected in series with each other and with the rheostats P.-

lt willbe readily seen fromv the diagram-- that in all the power positions of the control- 40 ler the circuit through-the brakc-magnctsM? is open at the switch AS. ,VVhen, however,

the controller is moved to its first brake position and the switch member P is shifted to engage the contacts p p these magnets are 43 included in the cl'osed local circuits of the 1110- tors. This circuit is from the brushes ofthe armat'ures in multiple to the blow-out coil; thenceto and. through the magnets M", thence to and through switch AS, thence to 5a and' through resistance R and'coils, M in series, thence through the field-coils of the motors in multiple, and back to the. negative brnshes'of the motors. In passing succes- .sively through positions 2, 3 and at sue 5 '5- cessi've sections of the resistance R are shortcircuited, so that at position 4 there is no external resistance iuth'e circuit. Then the [controller-switch is turned to its first power position, thecurrent iln the coils M is reversed 6o indirection and residual magnetism-in the.

brake-magnets is thereby neutralized. Th9 circnit'arraugement shown in Fig. 5 differs from that shown-in Fig. 4 in that the magnetcols M are not actively included in the 1o-' 5.

is -to say, the braking eitort of the motors rnhning as generators is alone used to slow circuit until position 4* is reached-that down the car, and the brake-shoes are brought into action only to bring the car to a full step. In the arrangement shown in this figure when the switch CS is turned to the first braking position 1 the circuit is as follows: From the positive brushes of the armatnres A A to and through the blowrout coil BOO, thence to and through switch AS, thence through resistan ce Rand magnets M to contact-finger 4, thence through the fields of the motorsin multiple to the negative brushes of the armatures. 'In position 2 the circuit is the same'as in position 1 with the exception of the fact that contact-finger 3 has become engaged with a contact on the switch-drum 10S, and thereby short-circuits one section of the resistance and also the magnets M At position 3 a second section of the resistance is short-circu'iiod by the engagement of contact-finger 2, and at position 4" the entire resistance short-circuited, and the current passesfrom .the switch AS through the magnet-coils M, and thence to con tactiinger c, which in this position is engaged with a contact of the said drum It il therefore be seen thatthe effect of turning the switch US through its several braking positions is first to graduallyremove from circuit the resistance It and in the last position to entirely-remove said re sistance and connect the-braking-coils in circuit instead,

The brake member 0 may, if desir ed,qbe

made of copper in order to increasethe brak ing effort by taking advantage of'the resulting induced current.

Bycausing the brakest'o be applieddirectly to the armature shaifts of the motors I gain the Moran tags of utilizing the red nctipn-gearing between the motors and the ar-axlesto multiply the braking elfort to. the axles..' My invention is, howeve r, applicabledirectly to the car-axles or to conntershafts between the axles and motors, if desired. Norda I- wish to'limit myself to the minor mechanical 18:.

too

tails herein shown and described, since tboso.

may be varied. w'ithoutydeparting from the.

spirit and scope of my'invention.

Having thus described my invention, what I claim, and desire to seizure by Letters Pat- 'ent,is- 1'.

1. In an electromagnetic brake, the combination of a rotary brake member, a bar of magnetic material capable of a movement to ward and away from the periphery ofsaid brake member, and havingpple-pieceswhich form shoes for eontact-with said surface, coils on e of the said pole-pie.c es,;mcans for euergizin'g said coils, means for sending areverse current 'aron'ndthe other of said pole;

away rom said -.b rake member.

-piec'es, anda springtezidingto hold sa id ban ;2."' n'a brisket-of the character described, I

Aihe combination of a, motor, a brake member on the armaturechaft thereof, a bar of magnetfc material supported to have a limited "movement toward and away from the said .brake member, said bar having two magnetcores formed with pole-pieces adapted for frictional contact with said-brake member,

I said her to hold it away from the brake mernthrough one Of the i In a z brakevof the char cter described, lthecol'nbiuation her, and means for sending a reverse current said ccils.

with a i'otaryl member havicg a peripheral brakingsm'fece, e pivoted mam 'gaps, coils on. said net-cerrieir, having p0le-picccs proyidc l wit-l1 shoes adapted to said braking-surfaces and normally sepemtccl 'bllcrcfrcm by short, eirpole-pieces, circuit connections for said coils, and means: for adjusting said her to vary the length of the said airgaps.

4-. In an electric brake, Lhecombinelicn with the (cirenctm-s, braking members on the m'metmrcslmfis of said motors, mid movable bmli i.'t--lll11 .li0t$ having pole-pieces for contact with said members, of suitable switch and circuitcci n circuit illrongh said meters and bli,l6-lllflg nets, and means else controlled by said switch for desiiiicyicg' tile I'C'Sillllill magnetism cf saidina-guets.

5.. In an electric brake, the combination eclicns for closing, a closed local with the caemotcrs, brake members on the armature -sl1ai'te of said. motors, movable brake-magmas heviz lg pole-pieces adapted for frictional contact with said brake memher, and resistance fer cennection in circuit with the meters, of a switchimving contacts and connections for connecting said meters in a closed local circuit with said resistance and by further movement thereof, to gi'etlually remove said resistance from, and connects the brake-magnets in the-said circuit, 6. In an electric brill; the combination with electiic mctoz f; in'akee'nagnetes, and resistance for connection in circuit with said. magnet-s, of switch mechanism having contacbs for connecting the motors in a clescd local circuifi including said resistance, and by further i'ncvei'ncut thereof to gradually remove said resistance and connect the brake maguces in said circuit;

In testimony whereof I have ellixed mysig- :xture in. presence of two WlCUQSSQS.

FRANK W. GARRETT. 

